研究者業績

服部 克巳

ハットリ カツミ  (Katsumi Hattori)

基本情報

所属
千葉大学 大学院理学研究院地球科学研究部門地球内部科学講座 教授
学位
博士(工学)(名古屋大学)
工学修士(名古屋大学)
工学士(名古屋大学)

J-GLOBAL ID
200901018537917126
researchmap会員ID
1000357254

外部リンク

論文

 196
  • Hongyan Chen, Peng Han, Jiancang Zhuang, Katsumi Hattori, Miao Miao, Kaiyan Hu, Tao Tao
    Geophysical Research Letters 2025年3月28日  
  • Xiaocan Liu, Peng Han, Yangkun Liu, Jiyao Xu, Katsumi Hattori, Huaran Chen, Liguo Jiao, Jiyao Tu
    Journal of Geophysical Research: Space Physics 2025年2月  
  • Ryota Kimura, Yoshiaki Ando, Leo Kukiyama, Tomoya Masuzawa, Katsumi Hattori, Masashi Hayakawa
    Radio Science 59(7) 2024年7月20日  
    Abstract Numerous studies have reported anomalous ultralow frequency (ULF) electromagnetic fields preceding earthquakes. In this paper, we estimate the current intensity responsible for generating the earthquake‐related ULF fields under the assumption that the origin is a current flowing at the hypocenter and that it has the same frequency dependence for all cases. To estimate current intensity, we perform ULF electromagnetic field simulations with an absorbing boundary condition developed in this study, taking into account the conductivity distribution of the Earth's crust. We analyze 11 earthquakes, including those that occurred in Loma Prieta, Spitak, Guam, Biak, Kagoshima, Iwateken Nairiku Hokubu, Izu swarm, Jammu and Kashmir, Alum Rock, Wenchuan, and L’Aquila. Our results show that, for nine out of the 11 events, there is a positive correlation between current intensity and earthquake magnitude, suggesting that the measured ULF fields originate from seismic activity and supporting our assumptions.
  • Jann-Yenq Liu, Xuhui Shen, Fu-Yuan Chang, Yuh-Ing Chen, Yang-Yi Sun, Chieh-Hung Chen, Sergey Pulinets, Katsumi Hattori, Dimitar Ouzounov, Valerio Tramutoli, Michel Parrot, Wei-Sheng Chen, Cheng-Yan Liu, Fei Zhang, Dapeng Liu, Xue-Min Zhang, Rui Yan, Qiao Wang
    Geoscience Letters 2024年1月20日  査読有り
    <jats:title>Abstract</jats:title><jats:p>The China Seismo-Electromagnetic Satellite (CSES), with a sun-synchronous orbit at 507 km altitude, was launched on 2 February 2018 to investigate pre-earthquake ionospheric anomalies (PEIAs) and ionospheric space weather. The CSES probes manifest longitudinal features of four-peak plasma density and three plasma depletions in the equatorial/low-latitudes as well as mid-latitude troughs. CSES plasma and the total electron content (TEC) of the global ionosphere map (GIM) are used to study PEIAs associated with a destructive M7.0 earthquake and its followed M6.5 and M6.3/M6.9 earthquakes in Lombok, Indonesia, on 5, 17, and 19 August 2018, respectively, as well as to examine ionospheric disturbances induced by an intense storm with the Dst index of − 175 nT on 26 August 2018. Anomalous increases (decreases) in the GIM TEC and CSES plasma density (temperature) frequently appear specifically over the epicenter days 1–5 before the M7.0 earthquake and followed earthquakes, when the geomagnetic conditions of these PEIA periods are relatively quiet, Dst: − 37 to 19 nT. In contrast, TEC and CSES plasma parameter anomalies occur globally in the southern hemisphere during the storm days of 26–28 August 2018. The CSES ion velocity shows that the electric fields of PEIAs associated with the M7.0 earthquake are 0.21/0.06 mV/m eastward and 0.11/0.10 mV/m downward at post-midnight/post-noon on 1–3 August 2018, while the penetration electric fields during the storm periods of 26–28 August 2018 are 0.17/0.45 mV/m westward/downward at post-midnight of 02:00 LT and 0.26/0.26 mV/m eastward/upward at post-noon of 14:00 LT. Spatial analyses on CSES plasma discriminate PEIAs from global effects and locate the epicenter of possible forthcoming large earthquakes. CSES ion velocities are useful to derive PEIA- and storm-related electric fields in the ionosphere.</jats:p>
  • Hongyan Chen, Peng Han, Katsumi Hattori
    IEEE Transactions on Geoscience and Remote Sensing 2024年  
  • Xiaocan Liu, Peng Han, Katsumi Hattori, Huaran Chen, Junjie Chen, Liguo Jiao, Jiyao Tu, Yu Lei, Junhao Zhao
    Journal of Geophysical Research: Space Physics 129 2024年1月  査読有り
  • Jann‐Yenq Liu, Tzu‐Hsun Kao, Tien‐Chi Liu, Bor‐Shouh Huang, Po‐Han Lee, Yang‐Yi Sun, Chieh‐Hung Chen, Katsumi Hattori, Po‐Han Liao, I.‐Te Lee, Ching‐Lun Su, Chuen‐Teyr Terng, Treng‐Shi Huang
    Geophysical Research Letters 2023年10月28日  査読有り
  • 太田悠一朗, 三浦健伸, 吉野千恵, 服部克巳, 今住則之
    42(2) 19-24 2023年10月  査読有り責任著者
  • Dimitar Ouzounov, Sergey Pulients, Jann-Yenq Liu, Katsumi Hattori, Menas Kafatos, Patrick Taylor
    2023年5月15日  
  • Hongyan Chen, Peng Han, Katsumi Hattori
    Remote Sensing 2022年11月  査読有り
  • Rui Song, Katsumi Hattori, Xuemin Zhang, Jann‐Yenq Liu
    Journal of Geophysical Research: Space Physics 2022年11月  査読有り責任著者
  • 木村亮太, 安藤芳晃, 服部克巳, 早川正士
    41(2) 52-57 2022年10月  査読有り
  • Satoru Kojima, Ryota Niwaa, Naoya Iwamoto, Heitaro Kaneda, Katsumi Hattori, Keitaro Komura, Tomohiro Yamazaki, Kazuki Yasunaga
    応用地質 63(1) 1-11 2022年4月  査読有り
  • Weiyun Xie, Katsumi Hattori, Peng Han, Haixia Shi
    ENTROPY 24(4) 2022年4月  査読有り責任著者
    The Gutenberg-Richter b value describes the ratio between large and small events. A number of studies have suggested that the b value decreases before large earthquakes. In this study, we investigate the temporal variation of the b value of an area along the main rupture zone of the 2008 Wenchuan earthquake (M8.0) prior to the great event. Before estimating b values, we tested the earthquake catalog to make sure that we use the reliable frequency-magnitude distribution by the calculation of MC (completeness of magnitude). We define parameter P (Delta AIC >= 2) values to examine the significance level of b-value changes in the temporal variation by combining a boostrap method with Akaike's Information Criterion (AIC). The b value in the main rupture zone shows a long-term decrease trend. We then focus on a smaller area where the initial rupture starts. The results show that b values significantly changed about 3 months before the 2008 Wenchuan earthquake in the initial rupture area, indicating that the b value has a potential capability to monitor and detect precursory phenomena of great earthquakes.
  • Katsumi Hattori, Kazuhide Nemoto, Haruna Kojina, Akitsugu Kitade, Shu kaneko, Chie Yoshino, Toru Mogi, Toshiharu Konishi, Dimitar Ouzounov
    2022年3月28日  
  • Valeria Satriano, Roberto Colonna, Angelo Corrado, Alexander Eleftheriou, Carolina Filizzola, Nicola Genzano, Hattori Katsumi, Mariano Lisi, Nicola Pergola, Vallianatos Filippos, Valerio Tramutoli
    2022年3月28日  
  • 根本和秀, 小島春奈, 吉野千恵, 金子柊, 北出明嗣, 服部克巳, 茂木透, 小西敏春
    40(1) 37-41 2021年11月  査読有り責任著者
  • Rui Song, Katsumi Hattori, Xuemin Zhang, Chie Yoshino
    Journal of Atmospheric and Solar-Terrestrial Physics 219 105628-105628 2021年8月  査読有り責任著者
  • Rui Song, Katsumi Hattori, Xuemin Zhang, Jann‐Yenq Liu, Chie Yoshino
    Journal of Geophysical Research: Space Physics 126(6) 2021年6月  査読有り責任著者
  • Hongyan Chen, Miao Miao, Ying Chang, Qiao Wang, Xuhui Shen, Katsumi Hattori, Peng Han
    Frontiers in Earth Science 9 2021年5月28日  査読有り
    Early studies have shown evidence of the seismo-ionospheric perturbations prior to large earthquakes. Due to dynamic complexity in the ionosphere, the identification of precursory ionospheric changes is quite challenging. In this study, we analyze the total electron content (TEC) in the global ionosphere map and investigate the TEC changes prior to M ≥ 6.0 earthquakes in the Chinese Mainland during 1998–2013 to identify possible seismo-ionospheric precursors. Singular spectrum analysis is applied to extract the trend and periodic variations including diurnal and semi-diurnal components, which are dominated by solar activities. The residual ΔTEC which is mainly composed of errors and possible perturbations induced by earthquakes and geomagnetic activities is further investigated, and the root-mean-square error is employed to detect anomalous changes. The F10.7 and Dst index is also used as criterion to rule out the anomalies when intense solar or geomagnetic activities occur. Our results are consistent with those of previous studies. It is confirmed that the negative anomalies are dominant 1–5 days before the earthquakes at the fixed point (35°N, 90°E) during 0600–1000 LT. The anomalies are more obvious near the epicenter area. The singular spectrum analysis method help to establish a more reliable variation background of TEC and thus may improve the identification of precursory ionospheric changes.
  • Xiaocan Liu, Peng Han, Katsumi Hattori, Huaran Chen, Chie Yoshino, Xudong Zhao, Liguo Jiao, Xinxin Ma, Yu Lei
    Journal of Geophysical Research: Space Physics 126(3) 2021年3月  査読有り
  • Zining Yu, Katsumi Hattori, Kaiguang Zhu, Mengxuan Fan, Dedalo Marchetti, Xiaodan He, Chengquan Chi
    Remote Sensing 13(3) 515-515 2021年2月1日  査読有り
    In order to monitor temporal and spatial crustal activities associated with earthquakes, ground- and satellite-based monitoring systems have been installed in China since the 1990s. In recent years, the correlation between monitoring strain anomalies and local major earthquakes has been verified. In this study, we further evaluate the possibility of strain anomalies containing earthquake precursors by using Receiver Operating Characteristic (ROC) prediction. First, strain network anomalies were extracted in the borehole strain data recorded in Western China during 2010–2017. Then, we proposed a new prediction strategy characterized by the number of network anomalies in an anomaly window, Nano, and the length of alarm window, Talm. We assumed that clusters of network anomalies indicate a probability increase of an impending earthquake, and consequently, the alarm window would be the duration during which a possible earthquake would occur. The Area Under the ROC Curve (AUC) between true predicted rate, tpr, and false alarm rate, fpr, is measured to evaluate the efficiency of the prediction strategies. We found that the optimal strategy of short-term forecasts was established by setting the number of anomalies greater than 7 within 14 days and the alarm window at one day. The results further show the prediction strategy performs significantly better when there are frequent enhanced network anomalies prior to the larger earthquakes surrounding the strain network region. The ROC detection indicates that strain data possibly contain the precursory information associated with major earthquakes and highlights the potential for short-term earthquake forecasting.
  • N. Genzano, C. Filizzola, K. Hattori, N. Pergola, V. Tramutoli
    Journal of Geophysical Research: Solid Earth 126(2) 2021年2月  査読有り
  • M. Parrot, V. Tramutoli, Tiger J. Y. Liu, S. Pulinets, D. Ouzounov, N. Genzano, M. Lisi, K. Hattori, A. Namgaladze
    The European Physical Journal Special Topics 230(1) 197-225 2021年1月  査読有り
  • Zining Yu, Kaiguang Zhu, Katsumi Hattori, Chengquan Chi, Mengxuan Fan, Xiaodan He
    IEEE Access 9 12167-12179 2021年1月  査読有り
  • Hongyan Chen, Rui Wang, Miao Miao, Xiaocan Liu, Yonghui Ma, Katsumi Hattori, Peng Han
    Entropy 22(11) 1270-1270 2020年11月9日  査読有り
    In order to find out whether the geomagnetic storms and large-mega earthquakes are correlated or not, statistical studies based on Superposed Epoch Analysis (SEA), significance analysis, and Z test have been applied to the Dst index data and M ≥ 7.0 global earthquakes during 1957–2020. The results indicate that before M ≥ 7.0 global earthquakes, there are clearly higher probabilities of geomagnetic storms than after them. Geomagnetic storms are more likely to be related with shallow earthquakes rather than deep ones. Further statistical investigations of the results based on cumulative storm hours show consistency with those based on storm days, suggesting that the high probability of geomagnetic storms prior to large-mega earthquakes is significant and robust. Some possible mechanisms such as a reverse piezoelectric effect and/or electroosmotic flow are discussed to explain the statistical correlation. The result might open new perspectives in the complex process of earthquakes and the Lithosphere-Atmosphere-Ionosphere (LAI) coupling.
  • 小島春奈, 吉野千恵, 根本和秀, 服部克巳, 小西敏春, 古屋隆一
    39(1) 46-51 2020年11月  査読有り責任著者
  • 金子柊, 茂木透, 服部克巳
    39(1) 37-41 2020年10月  査読有り責任著者
  • Qinghua Huang, Peng Han, Katsumi Hattori, Hengxin Ren
    Seismoelectric Exploration: Theory, Experiments, and Applications 415-436 2020年10月  査読有り
  • Zining Yu, Katsumi Hattori, Kaiguang Zhu, Chengquan Chi, Mengxuan Fan, Xiaodan He
    Entropy 22(10) 1086-1086 2020年9月27日  査読有り
  • Rui Song, Katsumi Hattori, Xuemin Zhang, Saito Sanaka
    Journal of Atmospheric and Solar-Terrestrial Physics 205 2020年9月1日  査読有り責任著者
    © 2020 Elsevier Ltd In this study, we investigated the characteristics of pre-earthquake ionospheric effects related to four successive shallow-focus earthquakes (M6.4 on July 28, 2018, M6.8, 5.9, 6.9 on August 05, 09 and 19, 2018) in Indonesia by the China Seismo-Electromagnetic Satellite (CSES). By adopting the moving median method (MMM), the ionospheric electron density (Ne) detected by the Langmuir probe (LAP) onboard CSES presented remarkable enhancements along the orbits #2660-0 on July 27, #2721-0 and #2728-1 on July 31, #2827-0 and #2735-1 on August 7, #2934-0 on August 14, respectively, which were just 1, 5, 2 and 5 days before the four earthquakes. Moreover, the disturbances mainly appeared in the north and north-east within the distance of 2000 km from each epicenter. By comparing the disturbed orbits with their corresponding four nearest and four revisiting orbits as well as the predicted values from the International Reference Ionosphere 2016 model (IRI-2016), the results powerfully illustrated that CSES observed the ionospheric precursors preceding the four Indonesian earthquakes. To make the space-borne results more convincing, we further studied the grid total electron content (TEC) data from the Center for Orbit Determination in Europe (CODE), which exhibited similar anomalies in both the temporal and spatial distributions. In the end, the superposed epoch analyses (SEA) method was conducted on 35 M ⩾ 5.8, depth⩽50 km earthquakes in Indonesia during 2007–2017 by using CODE TEC. The statistical results demonstrated that there were significant positive anomalies 1–7 days before earthquakes within 2000 km from the epicenters in this region. The positive plasma perturbations detected by CSES were highly suggested as the seismic-ionospheric effects before earthquakes.
  • Peng Han, Jiancang Zhuang, Katsumi Hattori, Chieh Hung Chen, Febty Febriani, Hongyan Chen, Chie Yoshino, Shuji Yoshida
    Entropy 22(8) 2020年8月  査読有り
    © 2020 by the authors. In order to clarify ultra-low-frequency (ULF) seismomagnetic phenomena, a sensitive geomagnetic network was installed in Kanto, Japan since 2000. In previous studies, we have verified the correlation between ULF magnetic anomalies and local sizeable earthquakes. In this study, we use Molchan's error diagram to evaluate the potential earthquake precursory information in the magnetic data recorded in Kanto, Japan during 2000-2010. We introduce the probability gain (PG') and the probability difference (D') to quantify the forecasting performance and to explore the optimal prediction parameters for a given ULF magnetic station. The results show that the earthquake predictions based on magnetic anomalies are significantly better than random guesses, indicating the magnetic data contain potential useful precursory information. Further investigations suggest that the prediction performance depends on the choices of the distance (R) and size of the target earthquake events (Es). Optimal R and Es are about (100 km, 108.75) and (180 km, 108.75) for Seikoshi (SKS) station in Izu and Kiyosumi (KYS) station in Boso, respectively.
  • Rika Tsutsumi, Katsumi Hattori, Chie Yoshino, Nicola Genzano
    Remote Sensing 12(16) 2020年8月  査読有り責任著者
    © 2020 by the authors. We proposed a cloud discrimination method applicable in Japan using MODIS nighttime data, monitored the singularity of the spatiotemporal correlation of surface temperature anomalies and investigated the possibility of detecting and monitoring lava activity in Shinmoedake. With the aim to detect lava eruption activity in 2011, nine years of data from 2003 to 2011 were analyzed. As a result, the first anomalous singularity in brightness temperature was detected on 26 January 2011. Moreover, the maximum value was detected on 30 January 2011. The values showed larger ones until early February 2011. When an anomalous singularity appeared, it was the only period with the magma-related volcanic activity for Shinmoedake over the analyzed period of nine years. The above facts indicate the effectiveness of the proposed singularity method to monitor the lava activity for Shinmoedake. Therefore, it is concluded that if cloud discrimination is realized with high accuracy, no spurious changes will come to arise, and no false detection of hotspots will be given.
  • Jann-Yenq Liu, Chi-Yen, Liu, Yuh-Ing Chen, Tso-Ren Wu, Meng-Ju Chung, Tien-Chi Liu, Yu-Lin Tsai, Loren C. Chang, Chi-Kuang Chao, Dimitar Ouzounov, Katsumi Hattori
    Geoscience Letters 7(1) 11-11 2020年  査読有り
  • Xiaocan Liu, Katsumi Hattori, Peng Han, Huaran Chen, Yoshino Chie, Xudong Zhao
    Pure and Applied Geophysics 177(1) 333-346 2020年1月1日  査読有り
    © 2019, Springer Nature Switzerland AG. We investigated observational data from 20 geomagnetic observatories at longitudes of 130°E to 150°E between 2009 and 2012 in order to detect possible anomalous changes in the geomagnetic solar quiet daily (Sq) variation related to the 2011 off the Pacific coast of Tohoku earthquake (Mw 9.0) that occurred on March 11, 2011, in Japan. We selected the five quietest days in every month and analyzed three-component magnetic data with 1-min resolution using the natural orthogonal component method to identify Sq variations from observations, and performed spherical harmonic analysis (SHA) to separate the internal and the external equivalent Sq current systems of Je and Ji. We found that Je and Ji were distorted near the epicenter on two geomagnetic quiet days, January 23 and 27, 2011. This was about 2 months before the earthquake. We then employed backward computation on the external and internal parts of the SHA model geomagnetic fields, Be and Bi, to determine the possible anomalous magnetic field variations at each station. The results showed significant differences in daily variation for all components on January 23 and 27, 2011. On the other days, we could not recognize any apparent anomalous behaviors apart from known secular, seasonal, and solar activity dependence. A possible connection between this anomaly and the very strong Tohoku earthquake, which followed only 1.5 months after the geomagnetic anomaly, is of extreme interest for research on earthquake precursors.
  • Jann Yenq Liu, Chi Yen Lin, Yu Lin Tsai, Tien Chi Liu, Katsumi Hattori, Yang Yi Sun, Tso Ren Wu
    Journal of Earthquake and Tsunami 13(5-6) 2019年10月1日  査読有り
    © 2019 World Scientific Publishing Company. Tsunami waves can induce tsunami traveling ionospheric disturbances (TTIDs) of the total electron content (TEC). In this study, we examine the TEC derived by ground-based receivers of the global positioning system (GPS) and identify TTIDs induced by 2004 Indian Ocean tsunami. Simulations of the COMCOT (Cornell multi-grid coupled tsunami) model and analyses of the circle method, the ray-tracing technique, and the beam-forming technique are used to show that TTIDs can be quickly detected and confirmed after the tsunami occurrence. Finally, the ionospheric TEC derived by existing ground-based GNSS (Global Navigation Satellite Systems) receiving stations is demonstrated to be useful to support the tsunami early warning system.
  • M. Nasucha, Yohandri, J. T.S. Sumantyo, K. Hattori, H. Kuze
    Journal of Physics: Conference Series 1185(1) 2019年5月1日  査読有り
    © 2019 Published under licence by IOP Publishing Ltd. Ultrasonic wave is suitable to be used as information carrier in short-range remote sensing practices. When developing a short-range ultrasonic remote sensing device, the object distance measurement routine shall produce an accurate result. In a few-meter or several-meter object detection or imaging, millimeter accuracy is required, therefore, a calibration becomes crucial. This article addresses the process and the result of our research on calibrating the distance between the device and the backscattering object. Our approach consists of investigating potential delay contributors, recognizing the practical delay contributors by analysing the program routine, formulating the calibration equation and applying the calibration equation in the computation.
  • Valerio Tramutoli, Francesco Marchese, Alfredo Falconieri, Carolina Filizzola, Nicola Genzano, Katsumi Hattori, Mariano Lisi, Jann Yenq Liu, Dimitar Ouzounov, Michel Parrot, Nicola Pergola, Sergey Pulinets
    Geosciences (Switzerland) 9(4) 2019年4月  査読有り
    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. In this work, we assessed the possible relation of ionospheric perturbations observed by Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER), Global Positioning System total electron content (GPS TEC), National Oceanic and Atmospheric Administration (NOAA)-derived outgoing longwave-Earth radiation (OLR), and atmospheric chemical potential (ACP) measurements, with volcanic and Saharan dust events identified by ground and satellite-based medium infrared/thermal infrared (MIR/TIR) observations. The results indicated that the Mt. Etna (Italy) volcanic activity of 2006 was probably responsible for the ionospheric perturbations revealed by DEMETER on 4 November and 6 December and by GPS TEC observations on 4 November and 12 December. This activity also affected the OLR (on 26 October; 6 and 23 November; and 2, 6, and 14 December) and ACP (on 31 October-1 November) analyses. Similarly, two massive Saharan dust episodes, detected by Robust Satellite Techniques (RST) using Spinning Enhanced Visible and Infrared Imager (SEVIRI) optical data, probably caused the ionospheric anomalies recorded, based on DEMETER and GPS TEC observations, over the Mediterranean basin in May 2008. The study confirmed the perturbing effects of volcanic and dust events on tropospheric and ionospheric parameters. Further, it demonstrated the advantages of using independent satellite observations to investigate atmospheric phenomena, which may not always be well documented. The impact of this increased detection capacity in reducing false positives, in the framework of a short-term seismic hazard forecast based on the study of ionospheric and tropospheric anomalies, is also addressed.
  • Weiyun Xie, Katsumi Hattori, Peng Han
    Entropy 21(3) 2019年3月1日  査読有り責任著者
    © 2019 by the authors. The Gutenberg-Richter Law describes the frequency-magnitude distribution of earthquakes. A number of studies have shown that the slope (b value) of the relationship between frequency and magnitude decreased before large earthquakes. In this paper, we investigate the temporal variation of the b value off the Pacific coast of Tokachi, Hokkaido, Japan, during 1990-2014. The magnitude of completeness (Mc) in the catalog is evaluated by combining the maximum curvature (MAXC) technique and the bootstrap approach. Then, the b value, and its uncertainty, is computed by using the maximum likelihood estimation. The Akaike Information Criterion (AIC) with the bootstrap approach is introduced to statistically assess the temporal variation of b values and quantify the significance level. The results show a decrease in trends of the b value prior to two large earthquakes (26 September 2003 (M8.0) and 11 September 2008 (M7.1)) in the analyzed area. In addition, the decrease of b values shows certain statistical significance three months before the 2003 Earthquake off the Pacific coast of Tokachi (M8.0). It is concluded that the b value with statistical assessment may contain potential information for future large earthquake preparation off the Pacific coast of Tokachi, Hokkaido, Japan.
  • Yuanyuan Zhou, Ying Chang, Hao Chen, Yong Zhou, Yonghui Ma, Chengliang Xie, Zhanxiang He, Katsumi Hattori, Peng Han
    Acta Geophysica Sinica 62(2) 572-586 2019年2月1日  査読有り
    © 2019, Science Press. All right reserved. Along with the development of urban constructions, artificial disturbances in geomagnetic observations are becoming more and more tremendous. The near-field noises produced by human activities such as vehicles, subway and high-speed railways make it difficult to precisely measure geomagnetic pulsations on the ground, thus reducing the practical application value of geomagnetic data. Therefore, suppressing near-field noises has scientific significance and application value. In this study, by combining remote reference and blind source separation analysis methods, we proposed a new signal processing approach which is able to separate geomagnetic pulsation from near-field noise. First, we demonstrated the effectiveness of the new approach by separating signals of different sources in the simulation analysis. Then, we applied this method to geomagnetic field data observed in Chiba, Japan where DC-driven train noises were intense. The results showed that geomagnetic pulsations and train noises are separated clearly, and near-field train noise could be reduced effectively on that basis. It is concluded that the reference-based blind source separation analysis is useful in extracting geomagnetic pulsations and suppressing near-field noises, and may have potential application value in electromagnetic exploration.
  • 大村潤平, 大山佳織, 韓鵬, 吉野千恵, 小島春奈, 服部克巳, 下道國, 小西敏春, 古屋隆一, 山口弘輝
    Journal of Atmospheric Electricity 38 37-52 2019年  査読有り責任著者
  • Peberlin P. Sitompul, Josaphat T. Sri Sumantyo, Farohaji Kurniawan, Cahya Edi Santosa, Timbul Manik, Katsumi Hattori, Steven Gao, Jann Yenq Liu
    Progress In Electromagnetics Research C 90 225-236 2019年  査読有り
    © 2019, Electromagnetics Academy. All rights reserved. In this paper, a circularly polarized slot-patch antenna for nanosatellite is presented. The novel design of the circularly polarized wave conducted by two asymmetrical rectangular-truncation techniques implemented on a circularly-slotted-patch on the front side and a deformed-shifted-feedline on the back side of the substrate. The antenna is printed on substrates with the dielectric constant of 2.17 and thickness of 1.6mm. The resonant frequency of the proposed antenna is set at 2.2 GHz with the minimum requirement of the axial ratio bandwidth (ARBW) of 300 MHz. The proposed antenna produces under 10 dB impedance bandwidth (IBW) 1.2765 GHz or equal to 58% (1.7235-3 GHz) with Left-Handed Circular Polarization (LHCP). The average antenna gain reaches 4.5 dBic at 2.2 GHz and the ARBW 327.5MHz or about 14.88% (2.0275-2.355 GHz). This paper includes the description and presentation of the completed discussion.
  • Katsumi Hattori, Peng Han
    Pre-Earthquake Processes 229-240 2018年6月11日  筆頭著者
  • Dimitar Ouzounov, Sergey Pulinets, Jann‐Yenq, Tiger) Liu, Katsumi Hattori, Peng Han
    Pre‐Earthquake Processes: A Multidisciplinary Approach to Earthquake Prediction Studies, edited by Ouzounov et al., Wiley 339-359 2018年6月11日  査読有り
  • Jann‐Yenq (Tiger) Liu, Katsumi Hattori, Yuh‐Ing Chen
    Pre‐Earthquake Processes: A Multidisciplinary Approach to Earthquake Prediction Studies, edited by Ouzounov et al., Wiley 305-317 2018年6月11日  査読有り

MISC

 243

書籍等出版物

 8

共同研究・競争的資金等の研究課題

 50